Process for producing copying foils



Patented July 1, 1924.

EUGEN SEYFFERTH, OF BERLIN, GERMANY.

PROCESS FOR PRODUCING COPYING FOILS.

No Drawing.

T 0 all whom it may concern:

Be it known that I, EUGEN Snrrnnnrn, citizen of Germany, residing at 2Panoramastn, Berlin, Germany, have invented a new and useful Improvementin the Processes for Producing Copying Foils; and I do hereby declarethe following to be a full, clear, and exact description of the same.

This invention relates to an improved process for producing copyingfoils for photo-mechanical transfer purposes. It iswell known thathitherto the transfer for photo mechanical purposes, or photographicpositives or negatives, on transparent paper, tracing paper and the likeof letter press printing, illustrations of all kinds, music, and drawingor writing, was effected by copying the object upon a sensitive layer ofchromate by itself, or applied to a lithographic stone, metal plate, orthe like and then treating the thus obtained transfers according to thepurpose for which they were intended.

The processes hitherto employed had many very serious defects. It israther difficult to put together the design to be copied, Withoutcutting up the glass plates, and the difierent thickness of the glasscauses trouble during the copying process.

It is, on the other hand, a matter of ex perience that the films ofdesignspulled oif glass plates can be handled only with difficulty, andcannot easily be cut to the desired oval or other shape, because thefilms are very thin and are liable to become damaged, and have atendency to curl or frizzle. Designs on tissue-paper are also ratherunsatisfactory for photo-mechanical transfers, inasmuch as it isnecessary to handle the ex tremely thin and easily torn tissue-papervery carefully, owing to its tendency to crease. Tissue-paper isfurthermore unequally milky or cloudy and does not possess sufficienttransparency. The insertion of printed pictures in places left vacant inthe form also leads to unsatisfactory copies, owing to the double layerof paper interfering with the penetration of the light.

All these defects are effectively overcome Application filed November14, 1921. Serial No. 515,117.

by the present invention, according to which transparent plates or filmsof cellon (acct ylcellulose), are employed in place of tissue or similarpaper. In cases where the danger of fire exists, cellon(acetylcellulose) (so-called fire-proof or incombustible celluloid), isexclusively used. In the following description will be used, for thesake of brevity only, the term cellon, which must be understood to coverall similar plastic substances more or less suitable to serve ascarrieils, bearers or foundation for copying foi s.

The parts of the cellon not printed upon, allow the light to passthrough without obstructing it in any way, as transparent cellon is astransparent as the best glass and the time for exposure to the lighttherefore becomes constant. As the cellon, even in comparatively largepieces, is handy and strong, sheets once used can be washed and theprinting ink removed, whereupon they can be used over and over again forthe same purpose. Corrections or changes may also easily be made. As thecellon is very thin, superimposed layers do not cause any lack ofclearness in the copies and the results obtained are most excellent.

It is well known that it is not easy to print upon cellon. It istherefore necessary to especially prepare the face of the plate destinedto receive the impression. With this end in View the cellon plate is,prior to the printing, rubbed with amixture of glacial acetic acid andacetone, allowed to dry, and then the treated surfaces are printed onwith entirely satisfactory results. Thin films of positive or negativephotographs, screen photographs, line drawings and the like, drawn offglass plates may be applied to transparent cellon sheets, trimmed to thesize of the space left vacant in the form and cemented or otherwiseattached, and preferably at the corners. Foils attached in this mannermay easily be removed and replaced by others, or removed after use andstored until again wanted.

What I claim as my invention, and desire to secure by United StatesLetters Patent is:

An improved process for the production trations on thin foils of cellon,for their 10 of copying foils of cellon, comprising,treatphotomechanical transfer purposes. ing the surface of plates oftransparent cel- In testimony whereof I have signed my lon(acetyl-cellulose) with a mixture of glaname to this specification inthe presence of 5 cial acetic acid and acetone, allowing the twosubscribing witnesses.

plates to dry, whereby to effect equal recepi DR. EUGEN SEYFFERTH. tionof printing-ink by the thus treated Witnesses:

cellon, mechanically printing on the thus Dr. CONRAD CnMFERs,

prepared surface, and then applying illus- OTTO Morass.

